<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <title>Document</title>
    <style>
        button {
            width: 100px;
            height: 50px;
            font-size: 22px;
        }
        
        div {
            width: 300px;
            height: 300px;
            margin: 30px 0;
            background-color: skyblue;
        }
        
        .current {
            background-color: yellowgreen;
        }
    </style>
    <script src="jquery-1.11.1.js"></script>
    <script>
        $(function() {
            $('button').click(function() {
                $('div').toggleClass('current')
            })
        })
    </script>
</head>

<body>
    <button>切换</button>

    <div>牡丹虽好空入目，枣花最小结实诚;</div>
</body>

</html>